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Abstract Two interacting high‐speed solar wind streams (HSSs) and associated stream interaction regions (SIR) caused a moderate geomagnetic storm during 14–20 March 2016. The spatio‐temporal evolution of the total electron content (TEC) during the storm is studied by using Global Navigation Satellite System (GNSS) data. The moderate storm caused significant and long‐lasting changes on TEC within the polar cap (70–90 MLAT), at auroral and sub‐auroral latitudes (60–70 MLAT), and at mid‐latitudes (40–60 MLAT). A 25%–50% depletion in TEC was observed for six days in the day, dusk and dawn sectors in the polar cap region and in the day and dusk sectors at the auroral and sub‐auroral latitudes. Sub‐auroral polarization streams observed by the Defense Meteorological Satellite Program satellite contributed to the sub‐auroral dusk TEC decreases. At mid‐latitudes, TEC depletion was observed in all local time sectors 21 hr after the storm onset. It is suggested that ion‐neutral frictional heating causes the TEC depletions, which is further supported by the observed spatial correlation between TEC depletions and O/N2decreases at mid‐latitudes observed by TIMED/GUVI. The storm induced a prolonged positive phase at mid‐latitudes lasting 9 hr. In the polar cap, enhancements of TEC up to 200% were caused by polar cap patches. TEC increases were the dominant feature in the night and morning sectors within the auroral oval because of particle precipitation and resulted up to regionally averaged 6 TECU (200%) increases.
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This content will become publicly available on April 28, 2026
A Statistical Study of the Decreased TEC Region During Summer at Northern High Latitudes
Abstract Based on the vertical Total Electron Content (TEC) data observed by the Global Navigation Satellite System in the northern hemisphere, a large area of low plasma density during summer at high latitudes, termed decreased TEC region, was investigated statistically between 2014 and 2024. Compared with the classical depleted structures that usually occur in the nighttime F region at high latitudes during winter, decreased TEC region is usually found in the sunlit polar cap ionosphere during summer. The decreased TEC region is predominantly located in regions above 70° magnetic latitude for moderate and high solar activity. The lower‐TEC region is biased towards the dawn and midnight sectors. Along the 18:25–06:25 Magnetic Local Time meridian, the depth of the decreased TEC region reached 7.6TECu in 2014. The decreased TEC region is deeper for higher Kp (Kp > 2) than for low Kp (Kp ≤ 2).
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- PAR ID:
- 10612065
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 8
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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